Spark wires
 

Can anyone tell me how I can check if my spark plug wires need replacing? I have done a visual check on the outside and they look great. I do not know how old they are and I am trying to find out the reason why my truck is STILL shaking when going uphill. Thank you.

You could check continuity with an ohm meter but I don't think it will tell you much. I doubt that the wires are causing the shaking. I would start looking at drive train issues such as universal joints or transmission. One of the experts should chime in soon with some good advice. Good luck.

Thank you, my tranny shifts good with no problems, my u-joints are good at least they were last time I checked them, I have had all 3 of my drive shafts replaced and I have changed all my spark plugs so I am thinking it is a problem with either my spark plug wires or my ignition coils. I hooked my truck up to a code reader and it threw P0302 which indicates a cylinder 2 misfire so I am trying to eliminate one thing at a time, starting with the cheapest fix of course. Thanks again.

A cylinder 2 misfire will cause shaking under load.............I would look at the cap and rotor and check them for arcing and probably replace them or atleas cleaning off the "corrosion" on the contacts......400 grit sand paper works great for that

My truck doesn't have a cap or rotor, it has ignition coils, I wish it had, those I understand, lol. I checked all my wires and they are all at the same ohms .50 , now I need to find out how to check the coils.

swap the coil that the #2 wire is hooked to with another coil....reset the light and see if it pops a light on the new wire its on......I say its a bad coil (sorry i forgot what year your truck was)

My truck is a 2000 4X4, now I hooked up the scanner again, apparently I had the wrong info, it was a Ford I was using in the scanner (my first time using one personally), ANYWAYS I put in the info for a 2004 Chevy Silverado 4X4 (year is closest the scanner had) and it came back with the code B2725 Active transfer Case Mode Switch Malfunction. This makes more sense to me as my "Service 4X4" light has come on several times over the past year, I took it in to the dealer and they said it is OK. Will this code make my truck shake going up hill? Should I replace the unit or check the solder on it? Please help, thanks for your patience.

Dave

I tried messing with the soldering on the 4WD switch but that didn't stop the "Service 4WD" light from coming back on. When it did, I couldn't get it into 4WD unless I shut the engine off for awhile. I bought a new switch and now the problem is gone.

Just replace them that way you can know what you have. I have MSD wires on my truck I just put on this second set they last forever I found them on Ebay cheap.

RMCK490 and GMCTRUCKS, thank you very much.